Cerebral microbleeds: old leaks and new haemorrhages

Black dots in the brain parenchyma diagnosed in T2*-weighted magnetic resonance imaging should be interpreted in light of the patient's history as well as the location, number and distribution of the lesions and associated imaging findings. These dots will correspond to haemoglobin degradation products in most of the cases referred to as cerebral microbleeds in patients with small vessel disease. Cerebral microbleeds have a prevalence of 5.7 % (range 3.7-7.7%) and are observed more frequently with increasing age. cerebral microbleeds have been observed in 47-80% of the primary intracerebral haemorrhage patients and in 0-78% of the patients with ischaemic cerebrovascular disease and appear to be a general marker of various types of bleeding-prone, small vessel disease and a predictor of recurrent vascular events. The occurrence and the number of cerebral microbleeds are associated with the degree of cerebral white matter abnormalities. Current data does not support the hypothesis that cerebral microbleeds are associated with a higher risk for a clinically relevant intracerebral haemorrhage, after anticoagulation/antiaggregation therapy, or after thrombolytic therapy in stroke patients. Therefore, the current data do not support the general exclusion of patients from therapy based on the presence of cerebral microbleeds. In the future, cerebral microbleeds may be incorporated into the design of clinical trials of anticoagulation/antiaggregation drugs in stroke patients for potential individual stratification for both the risk of recurrent ischaemic stroke and for the risk of intracerebral haemorrhage.